DE 2,131,555, DE 3,000,524 and U.S. Pat. No. 5,324,473 describe that an aryl ester of a haloformic acid, i.e., an aryl haloformate, can be prepared by a process in which phosgene and an aromatic hydroxyl compound are caused to react in the presence of such a catalyst as an amine derivative or a phosphorus compound. This process has disadvantages in that the toxic phosgene is necessarily employed and a great amount of an alkali is used.
It is known that an aryl ester of an aromatic carboxylic acid such as aryl benzoate can be prepared by reacting phenol with an aromatic carboxylic acid or an aromatic carboxylic acid chloride.
The diaryl carbonate is heretofore prepared by causing a reaction between phosgene and an aromatic hydroxyl compound in the presence of an alkali (see Japanese Patent Provisional Publication No. 62(1987)-190146). This process has disadvantages in that the toxic phosgene is necessarily employed and a great amount of an alkali is used.
The diaryl carbonate is also prepared by a process which comprises transesterification between a dialkyl carbonate and an aromatic hydroxy compound in the presence of a catalyst (see Japanese Patent Publications No. 56(1981)-42577 and H1(1989)-5588). This transesterification process, however, also has a disadvantage in that its reaction rate is not high even if a highly active catalyst is employed. This means that a large scaled apparatus is required when a diaryl carbonate is produced in an industrially applicable scale.
Yuki Gosei Kagaku (Organic Synthetic Chemistry in Japan), 5, Report 47, pp. 70-71(1948) teaches a reaction in which diphenyl oxalate is heated to release carbon monoxide to give diphenyl carbonate. This report does not mention with respect to the yield and selectivity of the reaction. According to a trace experiment of the experiment set forth in this report, only a small amount of diphenyl carbonate is produced.
U.S. Pat. No. 4,544,507 describes that the carbonic acid dialkyl ester, i.e., dialkyl carbonate, can be prepared by heating a dialkyl oxalate in a liquid phase at 50.degree.-150.degree. C. in the presence of an alcolate catalyst. In the working example of the Patent, a diphenyl oxalate is heated in the presence of a potassium phenoxide catalyst only to give mainly the diphenyl oxalate, namely, the starting compound.